1. Field of the Invention
The present invention relates to a device for detachably fastening an electronic module to a vehicle wheel having a pneumatic tire with a spring element.
2. Discussion of Background Information
To transmit measurement data related to a vehicle wheel, e.g., air pressure, temperature, etc., from the wheels to a central evaluation device that is a part of the vehicle, it is necessary to affix an electronic module inside an air chamber of the vehicle wheel. The placement of the module should be made so that neither extremely intense centrifugal forces that occur while traveling at high speeds nor installation procedures required when changing a tire can cause damage.
The manner of attaching modules in the prior art, e.g., a rigid screw attachment of the module to a valve body or a screw connection of the module to the valve through a ball fitting, do not sufficiently fulfill the above-noted requirements.
Strap retainers that can be affixed in a drop base of a rim are known for fastening electronic components. However, due to different heat expansion coefficients of the rim and strap retainer, elastic spring elements have to be interposed between the strap retainer and the rim for compensation. Although it can be theoretically assumed that the strength of the module seat can be controlled by a choice of initial force or stress to be exerted, the elastic spring elements of this type do not completely eliminate adverse effects on strength.
Further, in dimensioning the strap retainer, it is necessary to consider the format and size of the rim to which the module is to be attached.
Additional disadvantages associated with these strap retainers arise from an unfavorable polygon of forces, i.e., due to introduction of centrifugal force and high tensile load in the strap retainer. Also, due to a conical shape in the drop base bottom of certain rim types, a uniform introduction of force into the strap retainer is complicated.